


The Best Promise

by Stacysmash



Category: Haikyuu!!
Genre: Aged-Up Character(s), Fluff, Humor, Kuroo is stressed but it's angst-free, Kuroo's a father, M/M, Single Dad AU, Tooth-Rotting Fluff, Written for the Kurodai Domestic Zine: Midnight to Morning Coffee, child is original character, sequel fic
Language: English
Status: Completed
Published: 2018-12-20
Updated: 2018-12-20
Packaged: 2019-09-23 17:26:13
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,381
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17084558
Author URL: https://archiveofourown.org/users/Stacysmash/pseuds/Stacysmash
Summary: After two years of dating Sawamura Daichi, an old rival from his high school volleyball days and his son's phys ed teacher, Kuroo is ready to take the next step. With the help of his son, he has the whole proposal planned out, so the rest should be easy... right?Sequel toA Perfect Fit





	The Best Promise

**Author's Note:**

> My contribution to Midnight to Morning Coffee: a Domestic Kurodai Zine!! Shout out to Astrid and her amazing abilities at putting everything together. 10/10 would do it again (*feverishly hoping to do it again*)

“I think I’m going to throw up,” Kuroo said as he checked his reflection in the bathroom mirror for the hundredth time. His hands trembled while he straightened his tie and ran them quickly through his perpetually disheveled hair. “This is a disaster; do you think I should slick it back?”

“No, Dad, you look fine!” Naoki groaned from where he was sitting on the edge of the bathtub. Kuroo turned to look at his seven-year-old son and pouted.

“Just fine? I was hoping for devastatingly handsome or ‘Dad, he won’t be able to resist you!’” He ended with his mock-Naoki voice, and his charming son responded by sticking out his tongue.

“You know Daichi-san blushes every time he sees you in a suit, but you’d look better if you stopped sweating.”

Kuroo frowned at the smirk curling on his son’s lips, thinking he definitely got his cheek from his mother. He had met Kimiko in college and they dated briefly, but as short as their romance was, the result was an unexpected pregnancy. Kuroo’s own mother raised him on her own and there was no way he was going to have Kimiko go through the same thing, so with the help of their parents they were able to raise him together as close friends. They worked their way through college and now Kimiko was a successful photojournalist traveling the world. Because she was away most of the time, Naoki lived with Kuroo permanently.

It was all thanks to Naoki that Kuroo was reacquainted with Sawamura Daichi, his high school rival. He still couldn’t believe his luck when he followed Naoki across the school lawn to meet his new physical education teacher to find Daichi standing there, smiling down at his son and roughing up his thick head of hair. It was like being catapulted back in time when any interaction with Karasuno's captain spread a strange warmth through his chest and his dimpled smile sent Kuroo's heart racing.

He snatched Daichi up as soon as he could before the other single mothers could get their claws in him. Two years later, and Kuroo was finally ready to take it to the next step. Honestly, he was ready to marry Daichi from the first time they had dinner together, but his logical side knew it was best to wait and make sure he was the one, especially since he had his son to worry about. Unfortunately, the teasing was relentless from both Naoki and Kenma, saying that he should just get on with it, but no more. He was going to make Daichi officially his, even if it killed him. Taking the hundred and first look in the mirror, he cringed and wondered if it was, in fact, killing him.

“You do have the ring, right?”

“Of course, I have— shit, where did it go?!” His heart felt like a runaway train as his hands patted every surface of his body until it landed back on his pocket which bulged slightly from the little box inside. He heaved a deep sigh of relief.

“Dad? Maybe you should have a drink before he gets here.”

“No way, I’m liable to have too much and then I’d just blurt it out when I answer the door.”

“Maybe that would be best,” Naoki giggled and squealed when Kuroo swept him up in his arms and threw him over his shoulder.

“Some help you are. Come on, we need to pack your bag for Kenma’s.”

“It’s already packed! You need to chill!”

“ _You_ need to chill.”

“You’re so nervous you can’t even come up with a better comeback!”

“I’m fine! I swear you take after Uncle Kenma more than anyone and you’re not even blood-related.”

There was a knock at the door, and Kuroo nearly dropped his son as he began panicking all over again. Luckily Naoki was half monkey (definitely from his mother’s side), and he climbed down Kuroo’s long frame himself. He wrapped his hands into Kuroo’s shirt and yanked him down, his big dark eyes serious and boring a hole through his soul

“Dad. You can do this. Now be a man and open that door!”

“Yes! I can— _be a man_? That’s it, I’m shipping you off to China.”

Naoki groaned and shoved Kuroo towards the door and then ran back into his room to get his bag. There was another knock reminding him of who was waiting, and Kuroo took a deep breath to steady his nerves. He finally opened the door to reveal Daichi standing there patiently, his smile deep enough to reveal his secret dimples and his body clad in a suit that was tailored for his muscular build. When Kuroo didn’t say anything, because he obviously forgot his own name as he eyed his boyfriend up and down, Daichi’s smile slipped as he looked him over carefully.

“Tetsu, are you okay?” He stepped forward and placed a hand on his forehead, his chocolate-brown eyes widening when he felt the dappling of sweat. “Are you not feeling well? Why didn’t you tell me? Here, get in. Is Naoki alright?”

Kuroo hardly got his mind working before he was ushered inside and shoved down onto the sofa.

“Hi, Daichi-san! Have a good time at dinner!” Naoki called as he skipped to the door with his backpack on.

“I don’t think we’re going, Nao. Your dad isn’t feeling well.”

Naoki stopped in his tracks and spun to face them. Kuroo was so nervous and dumbstruck his mind was having difficulty keeping up, and he locked eyes with Naoki to beg for help.

“Um, he’s not sick! He’s fine, I think he’s just struck by how handsome you look!”

Daichi paused in unbuttoning the top of Kuroo’s shirt to smile at Naoki.

“Ha, you’re sweet but I doubt that. We’ll just stay here, and I’ll take care of him. Did you want to stay here and help, or would you rather have fun at Kenma’s? I’m fine either way and I don’t think Tetsu’s brain is functioning enough to care.”

“I’ll stay at Kenma’s still, but he’s really not sick.”

“I’m not sick!” Kuroo finally spat out and both their heads jerked toward him. “Sorry, I’ve had a lot on my mind, so my brain is a little rattled, but I’m really not sick. Come on, we’ll be late for our reservation.”

Kuroo moved to stand, but Daichi placed his hand firmly against his chest to keep him in place.

“There’s no way you’re not sick, you look awful.”

“Oh, thanks,” Kuroo deadpanned, wishing that he had utilized his hair gel. Daichi snickered and ran his hands through Kuroo’s damp hair.

“That’s not what I meant. You look handsome, but you also look sick. You’re sweating, your cheeks are flushed, and I can feel your heart racing through my palm.”

“That’s… not because I’m sick.”

“Then why?”

Kuroo gulped, searching his brain for some excuse that wouldn’t give away any of his plans. He looked at Naoki for help, but his son looked as clueless as he.

“Come on, I’ll help you to bed. We’ll go there another time, I promise.”

“But--”

Kuroo didn’t stand a chance as Daichi wrapped his arm behind his back and helped him to his feet, ushering him straight into his bedroom and setting him on his bed.

“I’ll go ahead and order some food that’ll be good for your stomach. Get undressed and I’ll be back in a few.”

Kuroo blinked in disbelief as Daichi slipped his phone out of his pocket to search for the number and walked out of the room, patting Naoki’s head as he slid past him in the doorway.

“Dad!” Naoki hissed as he ran over to him and slapped his little palms against Kuroo’s cheeks to focus his attention. “You can still do this.”

“No, I can’t! It was going to be perfect and romantic, and now I have to wait.”

“Don’t wait, your heart won’t be able to take it! Listen, restaurant proposals are really overdone.”

“How would you know?”

“Uncle Kenma told me.”

“Why didn’t he tell me?!”

“He didn’t want to interfere, but it doesn’t matter. Just speak to him from your heart and tell him how you feel. That’ll be romantic enough.”

“You’ve been watching too many dramas.”

“ _You’ve_ been watching too many dramas.”

“How dare you use my comebacks against me.”

“Dad, focus! Wait for the right moment, propose, show him the ring and for the love of God, don’t smile.”

“Why can’t I smile?!”

“Cuz you do that smirky thing and he’ll think you’re joking.”

“I don’t always smirk.”

“What are you two arguing about in here?” Daichi asked from the doorway, and they both went rigid, their eyes wide with guilt. Daichi snorted and rolled his eyes as he walked into the room. “Food’s ordered and… you’re still dressed.”

“Sorry, I was distracting him. I’ll go to Kenma’s now and leave you two alone.”

“Do you need me to walk you?”

“Daichi-saaaan, I’m seven! Plus, he’s just down the hall.”

“Alright, tell him I said hi,” Daichi chuckled as Naoki waved goodbye, shooting one last serious glare at his father once Daichi’s back was turned before running off. “Now, let’s get these clothes off.”

Daichi’s hands immediately began unraveling Kuroo’s tie and undoing a few more buttons, and like a switch, Kuroo began returning to his usual self.

“Oh? Suddenly I’m not so upset at staying home tonight,” He purred as he slid his hands to Daichi’s waist and pulled him closer.

“Now that sounds more like you, but you’re sick and need to rest.”

“Daichi, I’m really not sick, I promise. I’m just worked up about something.”

Daichi paused in undressing him to narrow his eyes at him.

“What are you worried about?”

“I… it’s complicated.”

“You can’t tell me?” Daichi asked, his face wincing slightly and Kuroo began to panic all over again.

“It’s not that! I’m dying to tell you but it’s not something you just blurt out.”

“Is it bad?”

“No, it’s great! At least I think it is, and I hope you do, too.”

“Then what do you have to be afraid of?”

Kuroo stared up at Daichi’s face as he contemplated the question. What was he afraid of? Did he really think he’d say no or maybe it wasn’t the right time? Was he worried about the proposal going so wrong Daichi would tease him about it for the rest of his life? Yup, definitely that, but it seemed to matter less and less as Daichi smiled down at him, gently running his hand through his hair.

“I just wanted it to be perfect, but I’m not sure it’s possible anymore. Nao told me to just be honest, and I think he’s right. This question, it’s bigger than a fancy restaurant or a well-thought-out speech.” Kuroo paused and dug his hand into his pants pocket, searching for the little box before he chickened out. His fingers slid over the velvet and he smiled as he met Daichi’s gaze. “I love you, and I’m tired of having to wait for you to show up at our apartment every night and I despise it when you leave. Nao’s thought of you as another father practically the moment he met you and I hate it that we can’t technically call you a part of our family. Daichi… will you marry me?” He finally blurted out the words as he held out the box, opening it to reveal the ring inside. Daichi’s jaw dropped open as he gasped quietly, his eyes huge as he stared down at the metal circle in front of him. His eyes flickered between it and Kuroo before finally settling on Kuroo as his cheeks flushed a deep red.

“Are you serious? You’re really asking me to marry you?”

“Yes, of course, I’m— oh shit, am I smiling? I’m sorry, Nao told me not to smile.”

“Why aren’t you allowed to smile?”

“Because I smirk, and he said you might think I’m joking.”

Daichi laughed, his beautiful hearty laugh that always filled Kuroo’s chest with an exuberant joy. With a shake of his head, Daichi leaned down and brushed his lips against Kuroo’s.

“You are smiling, but it’s an honest one for once and I love it. And yes, I’ll marry you, Idiot.”

Kuroo’s arms wrapped around him in a heartbeat, yanking Daichi completely onto his lap as his lips enthusiastically peppered his face. Daichi laughed and grabbed his face to quell the motion, capturing Kuroo’s lips with his own in a deep, sensuous kiss. Kuroo sighed into Daichi’s warmth, feeling all his anxieties melt away. He shivered as Daichi’s fingers raked down his back, his pulse quickening from Daichi’s enthusiasm. He had been so worried about the proposal itself, he hadn’t even considered the obvious celebration afterwards. As one of Daichi’s hands slid into his hair and gripped tight, Kuroo’s mind began plummeting on a one-way track down South.

“Now we can finally get rid of these clothes,” Kuroo purred, slipping his fingers in the knot at Daichi’s throat and gave it a little tug to pull it loose.

“Definitely. We’ve hardly started and yours are already soaked from sweat,” Daichi teased, and if Kuroo hadn’t been so excited he would have knocked him off his lap. Instead, he leaned forward and kissed the smirk off his future husband’s face and did a brief mental calculation on which clothing items to would be the quickest to remove.

A knock from the front door suddenly rang out through the apartment and Daichi snorted at the murderous look that flashed across Kuroo’s face.

“That’ll be the delivery guy.” He leaned down and planted a kiss on Kuroo’s lips before slipping off his lap. “Food first, then we’ll lose the clothes.”

“That’s the best promise you’ve ever made me.”

Daichi rolled his eyes and held out his hand to help him up, looking unimpressed.

“Better than agreeing to marry you?”

Kuroo’s signature smirk curled on his lips as he accepted Daichi’s hand and snapped to his feet. Without letting go, he snatched the ring out of the box and slid it onto Daichi’s finger, planting a brief kiss on it with a wink.

“You’re right, second best promise.”

**Author's Note:**

> Believe it or not, A Perfect Fit was going to be my submission to the Kurodai zine, but it got too long, so I decided to make a sequel instead that could stand on its own, ha ha ha. I hope to write more single dad au's in the future, b/c they're cute shit.


End file.
